Prime Minister Atal Bihari Vajpayee's grandnephew was killed when some youths threw him out of a running train near Kosikalan in Uttar Pradesh's Mathura district on Sunday, according to a police spokesperson in Lucknow.

Manish Mishra, grandson of Vajpayee's sister Vimla Mishra, and two of his friends had tried to prevent the youths from teasing some girls travelling in the Chhattisgarh Express, he said on Monday.

The assaulters were allegedly in an inebriated state and they also threw out Mishra's friends, he said.

The police were informed in the morning when some villagers found Mishra, who had died of injuries, and one of his friends lying injured near the tracks.

There was no information about the other friend, he said.

Mishra was a BSc student in Mathura's BSA College, the spokesperson said. His father Mahendra Mishra is an employee in the Jindal Pipe Factory in the Kosikalan Industrial area, he added.

A case has been registered and efforts are on to trace the culprits, he added.

Vajpayee has left for Kosikalan to attend the funeral, a spokesperson at the prime minister's office said.